Insulating-knob



L. STEINBERGER.

INSULATING KNOB.

APPLICATION FlLED JAN.17, 1918.

1 348, 249. Patented Aug. 3, 1920.

IIVVENTOR UNITED STATES PATENT OFFICE.

LOUIS STEINBERGER, OF BROOKLYN, NEW YORK. v

INSULATING-KNOB.

Specification of Letters Patent.

Patented Aug. 3, 1920.

Application filed January 17, 1918. Serial No. 212,336.

of the borough of Brooklyn, county of Kings, city and State of New York, have invented certain new and useful Improvements in Insulating-Knobs, of which the following is a specification.

My invention is particularly adapted for use in radio installations, though its use is not limited to any particular form or manner of hand'operated key for making and breaking electrical contacts.

One of the objects of my invention is to so fashion and conduct the finger knobs of telegraph keys that the operator thereof will not receive electrical shocks.

Another object'is to-provide a protectlve insulating shield upon a keyknob between the metal lever of the key and the portion of the knob upon which the hand, of the operator is placed.

Another object is to so form the above mentioned protective insulating shield so that the operator will be protected from electrical shocks even though a current of high frequency besent through the apparatus.

Another object is to so utilize the part1cu-' lar insulating shield as to cause it to function also as a fin er or hand rest for the operator. Other ob ects will appear from the following description and claims.

Referring to the drawings: Figure 1 is an elevation of my improved insulating knob with a protective insulating shieldsecured to a key lever, the portion of the key lever at the point of connection be ing in section.

ig. 2 is an enlarged vertical section of a knob embodying my invention illustrating in elevation a means for attaching the same to the metal lever.

Fig. 3 is a plan of my improved knob,

looking at the underside of the protective shield.

Referring to the drawings, 10 is a' finger knob providedwith a flanged upper finger portion 11 of the usual form, from which I projects a stem or shank 12 for attachment to the key operated lever L. Projecting radially from the stem 12 at a point substantially midway thereof is a flange or shield 13 of greater diameter than thediatmeter of the finger portion of the knob. This flange or shield is preferably grooved or corrugated on the lower surface'thereof by form- STEINBERGER,

ing a series of alternately disposed grooves 16 and ridges 17 as shown, so that a reater insulating surface will be provided or the creepage of the current and thereby more effectually insulate and protect the'operator when currents of high frequencies are used. I Many means maybe employed for securing the knob to the metal key, one of which .is illustrated and which I .find to be very of the finger portion of the key knob and the insula ing material will fill up the slot 22 in the head 21 of the screw (which is normally provided for a screw driver) so that the screw willtherefore be securely and rigidly molded and held to the knob.

The projecting portion 23 of the screw shank 1s provided with screw threads 24 which are utilized to engage with the screw threads 25 in the hole 26 formed in the outer extremity of the key lever L when the knob Itis well known that the ease with which an operator can transmit is governed by the shape and proportions of the key knob,

namely, the diameter of the knob and the distance or height of the knob from the table, both of which contributes to a maximum transmitting speed. Not only have I brought about this proportion of key knob diameter to heightabove table, but the above mentioned protective insulating shield is so placed as to act also as a rest and afirm stop for the fingertips. 'Thus'the fingers are allowed to relax without loosing the necessary grip on the key. This condition not only increases: the ease with which the key can be manipulated butthe endurance of the operator is also increased thereby.'

The insulating material used in the con struction of this invention may be of anysuitable material of that nature, but I pre- Y Y ters Patent is:

fer to use the insulating materiaLwhich is known in the art'as electrose.

As changes of construction could be made within the scope of my invention, it. is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limitingsense.

Having now described my invention what I claim as new and desire to secureiby Let- 1. An insulating knob-for telegraph keys consisting of a finger portion, a shank and an insulating shield extending a material distance radially from the shank and at a point adjacent the finger portion, the said shield forming an insulated finger rest and protector for the remaininginactivefingers of the hand of the operator. '2. A key knob of insulting material, having a finger portion at one end and a finger rest andprotective insulating shield for the remaining inactive fingers of the hand of the operator, the said shield having a materially greater area than the said finger portion, and situated below and separated therefrom.

3. A key knob having. a body portion of insulating-material, a finger portion also of to and below the said finger portion, the said finger rest and shield having on its under surface a series of concentric grooves and' ribs, a metallic reinforcing element embedded within the central portion of the key knob and extending substantially therethrouglrl centrally thereof and projecting from the body portion at one end, provided with means for attachment to a key lever, the upper end of the metallic reinforcement being provided withmeans f r engagement -with the insulating material of the knob to prevent its turning axially. j I 5. A key knob consisting of a body por-= tion of insulating material, a finger operating portion at one end thereof, a protective insulating finger rest and shield of substantially greater area than the finger portion, projecting from th body portion adjacent to and below the said finger portion,

the said finger rest and shield having on its under surface a series of concentric grooves and ribs, a metallic reinforcing element embedded within the central portion'of the key knob and extending substantially there- 'through centrally thereof and projecting from the ,body portion at one end, provided with means for attachment to a key lever, the metallic reinforcement being provided with means for engagement with the insulating material of the knob to prevent its turning axially. L

In witness whereof I have hereunto set my hand at the borough of Manhattan, cit county and State of New York, this fifteenth day of January, 1918.

LOUIS STEINBERGER.

In presence of C. C. BILLINGS, ZITA M. GRAHAM. 

